Characterization of Surface Species during Benzene Hydroxylation over a NiO-Ceria-Zirconia Catalyst

Langmuir ◽  
2021 ◽  
Author(s):  
Jennifer N. Jocz ◽  
Yimeng Lyu ◽  
Bryan J. Hare ◽  
Carsten Sievers
Keyword(s):  
Surface Species ◽  
Zirconia Catalyst ◽  
Benzene Hydroxylation

scholarly journals Progress in the Characterization of the Surface Species in Activated Carbons by means of INS Spectroscopy Coupled with Detailed DFT Calculations

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Andrea Piovano ◽  
Andrea Lazzarini ◽  
Riccardo Pellegrini ◽  
Giuseppe Leofanti ◽  
Giovanni Agostini ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Inelastic Neutron ◽  
Industrial Applications ◽  
Surface Species ◽  
Dft Methods ◽  
Neutron Spectra ◽  
Out Of Plane ◽  
Bending Modes

Activated carbons are materials with relevance in different industrial applications. Due to the inherent complexity and heterogeneity of their structures, an easy assignment of the species present on their surface has a challenging result. Only recently, with the possibility to collect well-resolved inelastic neutron spectra and to simulate by DFT methods more or less extended graphitic clusters, this task is starting to become feasible. Here we report our investigation on a steam activated carbon and we show that different vibrations in the region of out-of-plane C-H bending modes are specifically connected to hydrogen terminations belonging to extended and regular borders or to short and defective ones. Furthermore, simulations including heteroatoms such as oxygen allowed us to point out spectral regions with a contribution from carboxyl species.

scholarly journals Proton-Detected Multidimensional Solid-State NMR Enables Precise Characterization of Vanadium Surface Species at Natural Abundance

2019 ◽  
Author(s):  
Deni Mance ◽  
Aleix Comas-Vives ◽  
Christophe Copéret
Keyword(s):  
Solid State Nmr ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Industrial Process ◽  
Vanadium Complex ◽  
Surface Species ◽  
Catalytic Surfaces ◽  
Fast Mas ◽  
Precise Characterization

Heterogeneous catalysts fulfill vital roles in industrial process, however due to the nature of the catalytic surfaces typically containing either a low abundance of active sites and being amorphous in nature leads difficulties when attempting to study the structure of the active sites. In this work we show how making use of fast MAS ssNMR probes allows to efficiently detect well resolved <sup>1</sup>H detected spectra of heterogeneous catalysts. This approach was applied to study the structure of surface species resulting from the grafting of VO(OiPr)<sub>3</sub> onto a partially dehydroxylated silica using the surface organometallic chemistry approach. The use of the <sup>1</sup>H sensitivity enabled to detect various hetero- and homo-nuclear correlation spectra in order to study the structure of this system and to resolve the structure of the grafted vanadium complex. More specifically, VO(OiPr)<sub>3</sub> grafts through both protonolysis and opening of siloxane bridges to generate a bis-grafted species, in contrast to most other alkoxides.<br>

Characterization of surface species of supported V2O5Al2O3 catalysts by 51V NMR

1991 ◽  
Vol 69 (1) ◽  
pp. 61-73 ◽  
Author(s):  
O.B. Lapina ◽  
V.M. Mastikhin ◽  
L.G. Simonova ◽  
Yu O. Bulgakova
Keyword(s):  
Surface Species ◽  
51V Nmr

Identification and characterization of sorbed lutetium species on 2-line ferrihydrite by sorption data modeling, TRLFS and EXAFS

2001 ◽  
Vol 89 (7) ◽  
Author(s):  
K. Dardenne ◽  
T. Schäfer ◽  
Melissa A. Denecke ◽  
J. Rothe ◽  
J. I. Kim
Keyword(s):  
Fine Structure ◽  
Low Ph ◽  
Hydrous Ferric Oxide ◽  
Surface Species ◽  
Sorption Data ◽  
X Ray ◽  
Capacity Model ◽  
X Ray Absorption ◽  
Identification And Characterization

The Lu(III) sorbed species onto synthetic hydrous ferric oxide (HFO), commonly called ferrihydrite, has been identified. Characterization of the synthetic 2-line HFO shows that its synthesis is reproducible. Potentiometric titration of freshly synthesized HFO, modeled using the constant capacity model (κEvaluation of chemical sorption data reveals the presence of two different Lu surface sorbed species, dependent on pH; a monodendate species forms at low pH and a polydentate species at pH>5. Satisfactory fits to the sorption data are obtained using a combination of monodentate and bidentate surface species. The combination of species is chosen, based on extended X-ray absorption fine structure (EXAFS) results. The sorption constants obtained from these fits are p

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